#include <fstream>
#include <vector>

using namespace std;

const int N = 16000;
int v[N + 1];
vector <int> la[N + 1];
bool viz[N + 1];
int suma[N + 1];

void dfs(int x)
{
    viz[x] = true;
    suma[x] = v[x];
    for (auto vec: la[x])
    {
        if (!viz[vec])
        {
            dfs(vec);
            if (suma[vec] > 0)
            {
                suma[x] += suma[vec];
            }
        }
    }
}
int main()
{
    ifstream in("asmax.in");
    ofstream out("asmax.out");

    int n;
    in >> n;
    for (int i = 1; i <= n; i ++)
    {
        in >> v[i];
    }
    for (int i = 1; i < n; i ++)
    {
        int x, y;
        in >> x >> y;
        la[x].push_back(y);
        la[y].push_back(x);
    }

    dfs(1);

    int smax = suma[1];
    for (int i = 2; i <= n; i ++)
    {
        smax = max(smax, suma[i]);
    }

    out << smax;

    in.close();
    out.close();

    return 0;
}